US4843040A - Silicon nitride sintered bodies - Google Patents
Silicon nitride sintered bodies Download PDFInfo
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- US4843040A US4843040A US07/012,159 US1215987A US4843040A US 4843040 A US4843040 A US 4843040A US 1215987 A US1215987 A US 1215987A US 4843040 A US4843040 A US 4843040A
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- ceramic article
- silicon nitride
- silicon carbide
- nitride sintered
- sintered body
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- 229910052581 Si3N4 Inorganic materials 0.000 title claims abstract description 58
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 title claims abstract description 58
- 239000011248 coating agent Substances 0.000 claims abstract description 53
- 238000000576 coating method Methods 0.000 claims abstract description 53
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims abstract description 46
- 229910010271 silicon carbide Inorganic materials 0.000 claims abstract description 43
- 230000003647 oxidation Effects 0.000 claims abstract description 25
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 18
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 16
- 238000005229 chemical vapour deposition Methods 0.000 claims description 11
- 229910052681 coesite Inorganic materials 0.000 claims description 8
- 229910052906 cristobalite Inorganic materials 0.000 claims description 8
- 239000000377 silicon dioxide Substances 0.000 claims description 8
- 229910052682 stishovite Inorganic materials 0.000 claims description 8
- 229910052905 tridymite Inorganic materials 0.000 claims description 8
- 230000004584 weight gain Effects 0.000 claims description 6
- 235000019786 weight gain Nutrition 0.000 claims description 6
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 claims description 4
- WMOUFOOEUAMQNE-UHFFFAOYSA-N [N].[O].[Si].[Y] Chemical compound [N].[O].[Si].[Y] WMOUFOOEUAMQNE-UHFFFAOYSA-N 0.000 claims description 4
- 229910052634 enstatite Inorganic materials 0.000 claims description 4
- 229910052839 forsterite Inorganic materials 0.000 claims description 4
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 claims description 4
- BBCCCLINBSELLX-UHFFFAOYSA-N magnesium;dihydroxy(oxo)silane Chemical compound [Mg+2].O[Si](O)=O BBCCCLINBSELLX-UHFFFAOYSA-N 0.000 claims description 4
- 239000006104 solid solution Substances 0.000 claims description 4
- 229910052727 yttrium Inorganic materials 0.000 claims description 4
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 claims description 4
- 239000000919 ceramic Substances 0.000 claims 21
- 230000000052 comparative effect Effects 0.000 description 7
- 239000007789 gas Substances 0.000 description 7
- 239000000654 additive Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000000996 additive effect Effects 0.000 description 3
- 229910021419 crystalline silicon Inorganic materials 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000006557 surface reaction Methods 0.000 description 2
- 229910003902 SiCl 4 Inorganic materials 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
- C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/5053—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials non-oxide ceramics
- C04B41/5057—Carbides
- C04B41/5059—Silicon carbide
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
- C04B41/85—Coating or impregnation with inorganic materials
- C04B41/87—Ceramics
Definitions
- This invention relates to a silicon nitride sintered body having an improved oxidation resistance or wear resistance.
- Silicon nitride sintered bodies are often used at their as-sintered or worked surfaces for gas turbine members and high temperature structural members.
- the surface of the silicon nitride sintered body is covered with a coating of silicon nitride by a chemical vapor deposition (CVD) process to eliminate the surface defects and enhance the strength prior to the use.
- CVD chemical vapor deposition
- the coating of silicon nitride is destroyed by reacting with the sintered body thereby losing the effect of the coating formation.
- a silicon nitride sintered body having on its surface a coating of silicon carbide.
- the coating of silicon carbide is formed of a CVD process.
- the surface of the silicon nitride sintered body having high strength at high temperatures but low oxidation resistance and wear resistance is covered with a crystalline silicon carbide coating having high oxidation resistance and wear resistance and a high coexistent property with the silicon nitride sintered body to provide a silicon nitride sintered body having particularly improved oxidation resistance or wear resistance at high temperatures.
- silicon nitride sintered body used herein means to include a pressureless sintered body, hot pressed or hot isostatic pressed sintered body and the like, which may occasionally contain various additives.
- the additives contained in the silicon nitride sintered body to be covered according to the invention are insignificant because the oxidation resistance or the wear resistance is improved by coating, so that it is possible to use any kind of silicon nitride sintered bodies.
- the thickness of the silicon carbide coating is dependent on the producing method, but it is preferably within a range of 10-300 ⁇ m.
- the silicon nitride sintered body generally has an as-sintered surface or a worked surface, either of these surfaces may be covered with the coating of silicon carbide.
- the following processes can be utilized for forming the silicon carbide coating a CVD process in a which SiCl 4 gas or the like is reacted with C 3 H 8 gas or the like in vapor phase to form a coating on the sintered body surface, a reaction sintering coating; process in which carbon is applied to the sintered body surface and then immersed in molten Si and reacted therewith at a temperature of 1,600°-1,700° C. to form a coating, a surface reacting carbonization process in which carbon is applied to the sintered body surface and heated at a temperature of 1,700° C. to conduct the formation of a coating through the following reaction;
- the formed silicon carbide is ⁇ type or ⁇ type crystalline.
- the thermal expansion coefficient of the silicon nitride sintered body is increased to be made close to that of silicon carbide as a coating.
- a crystalline phase having a high thermal expansion such as forsterite (2MgO ⁇ SiO 2 ), enstatite (MgO ⁇ SiO 2 ), yttrium silicate (Y 2 Si 2 O 7 ), yttrium-silicon-oxygen-nitrogen (Y--Si--O--N) or the like, or a solid solution thereof.
- samples were also prepared wherein the curved surface of each of the silicon nitride sintered bodies (Nos. 1-10) having a diameter of 35 mm and a thickness of 8 mm was covered with a silicon carbide coating having a thickness of 150-300 ⁇ m, samples wherein one surface of 6 mm ⁇ 16 mm of rectangular parallelpiped silicon nitride sintered bodies having a block form of 6 mm ⁇ 16 mm ⁇ 10 mm was covered with the silicon carbide coating, and samples of Comparative Examples wherein silicon nitride sintered bodies (Nos. 11, 13, 15, 17 and 19) having the same form as the above block form and no silicon carbide coating.
- the surface covered with the coating was mirror-finished to conduct a wear test at a temperature of 600° C. through a block on ring type machine.
- a load was 2 kg
- a rotating speed was 1,000 rpm
- a test period was 10 hours.
- From the wear volume of the rectangular parallelpiped samples was calculated a specific wear rate. The obtained results are shown in Table 1.
- the silicon nitride sintered bodies covered with the silicon carbide coating by CVD process according to the invention exhibit excellent oxidation resistance and wear resistance as compared with the silicon nitride sintered bodies having no coating.
- the silicon nitride sintered bodies covered with the silicon carbide coating according to the invention which were prepared by the surface reaction process, have considerably improved oxidation resistance as compared with the silicon nitride sintered bodies having no silicon carbide coating, but the improvement of wear resistance is not observed.
- the silicon nitride sintered bodies having the silicon carbide coating according to the invention which were prepared by the surface reaction process, have a considerably improved oxidation resistance as compared with the silicon nitride sintered bodies having no silicon carbide coating, but the improvement of wear resistance is not observed.
- the silicon nitride sintered body covered with the silicon carbide coating according to the invention possesses not only a high-temperature strength resulting from the silicon nitride sintered body itself but also high oxidation resistance and wear resistance resulting from the silicon carbide, which is applied to high temperature structural members such as engine parts, for example, a gas turbine engine rotor, a turbocharger rotor and the like to thereby improve the oxidation resistance or wear resistance thereof.
- the silicon carbide coating is particularly formed on the silicon nitride sintered body by CVD process, whereby the oxidation resistance and the wear resistance can simultaneously be improved.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Ceramic Products (AREA)
Abstract
A silicon nitride sintered body having an improved oxidation resistance or wear resistance has in its surface a coating of silicon carbide. Particularly, the coating of silicon carbide is formed by CVD process.
Description
1. Field of the Invention
This invention relates to a silicon nitride sintered body having an improved oxidation resistance or wear resistance.
2. Related Art Statement
Silicon nitride sintered bodies are often used at their as-sintered or worked surfaces for gas turbine members and high temperature structural members. On the other hand, as disclosed in Japanese Patent laid open Nos. 60-161,383 and 60-200,882, the surface of the silicon nitride sintered body is covered with a coating of silicon nitride by a chemical vapor deposition (CVD) process to eliminate the surface defects and enhance the strength prior to the use.
In these silicon nitride sintered bodies constituting the above member at their as-sintered or worked surfaces, however, when used at high temperature, the oxidation resistance and the wear resistance are deteriorated as compared with the case of using at room temperatures. Therefore, when they are used as a gas turbine member or a high temperature structural member, the service life is considerably shortened.
Further, in the silicon nitride sintered body covered with the coating of silicon nitride by the CVD process, the coating of silicon nitride is destroyed by reacting with the sintered body thereby losing the effect of the coating formation.
It is an object of the present invention to overcome the above-mentioned drawbacks and provide a silicon nitride sintered body which is particularly excellent in oxidation resistance or wear resistance at high temperatures.
According to the invention, there is the provision of a silicon nitride sintered body having on its surface a coating of silicon carbide. In particular, the coating of silicon carbide is formed of a CVD process.
According to the invention, the surface of the silicon nitride sintered body having high strength at high temperatures but low oxidation resistance and wear resistance is covered with a crystalline silicon carbide coating having high oxidation resistance and wear resistance and a high coexistent property with the silicon nitride sintered body to provide a silicon nitride sintered body having particularly improved oxidation resistance or wear resistance at high temperatures.
The term "silicon nitride sintered body" used herein means to include a pressureless sintered body, hot pressed or hot isostatic pressed sintered body and the like, which may occasionally contain various additives. However, the additives contained in the silicon nitride sintered body to be covered according to the invention are insignificant because the oxidation resistance or the wear resistance is improved by coating, so that it is possible to use any kind of silicon nitride sintered bodies. Further, the thickness of the silicon carbide coating is dependent on the producing method, but it is preferably within a range of 10-300 μm. This is due to the fact that when the thickness is less than 10 μm, it is difficult to obtain a uniform coating, while when it exceeds 300 μm, there remarkably appears a poor adhesion such as separation or the like resulting from the difference in thermal expansion coefficients between the silicon carbide coating and the silicon nitride sintered body. Furthermore, it is favorable that the thermal expansion coefficient of the silicon nitride sintered body to be covered be close to that of the silicon carbide as a coating.
The production of the silicon nitride sintered body according to the invention will be described below.
Although the silicon nitride sintered body generally has an as-sintered surface or a worked surface, either of these surfaces may be covered with the coating of silicon carbide.
The following processes can be utilized for forming the silicon carbide coating a CVD process in a which SiCl 4 gas or the like is reacted with C3 H8 gas or the like in vapor phase to form a coating on the sintered body surface, a reaction sintering coating; process in which carbon is applied to the sintered body surface and then immersed in molten Si and reacted therewith at a temperature of 1,600°-1,700° C. to form a coating, a surface reacting carbonization process in which carbon is applied to the sintered body surface and heated at a temperature of 1,700° C. to conduct the formation of a coating through the following reaction;
Si.sub.3 N.sub.4 +3C→3SiC+2N.sub.2.
Incidentally, according to any of the above-mentioned processes, the formed silicon carbide is α type or β type crystalline.
According to the invention, it is desirable that the thermal expansion coefficient of the silicon nitride sintered body is increased to be made close to that of silicon carbide as a coating. For this purpose, it is preferable that on the grain boundary of the silicon nitride sintered body is precipitated a crystalline phase having a high thermal expansion such as forsterite (2MgO·SiO2), enstatite (MgO·SiO2), yttrium silicate (Y2 Si2 O7), yttrium-silicon-oxygen-nitrogen (Y--Si--O--N) or the like, or a solid solution thereof.
The following examples are given in the illustration of the invention and are not intended as limitations thereof.
On an as-sintered or worked surface of a silicon nitride sintered body having a composition and a thermal expansion coefficient as shown in the following Table 1 was formed a coating of silicon carbide having a crystalline structure as shown in Table 1 by a CVD process using raw gases and temperatures shown in Table 1, to thereby obtain silicon nitride sintered bodies (Nos. 1-10) according to the invention.
Samples of the silicon nitride sintered bodies (Nos. 1-10) having a diameter of 30 mm and a thickness of 10 mm, the surfaces of which are covered with a silicon carbide coating having a thickness of 10-150 μm, and samples of silicon nitride sintered bodies (Nos. 11-20) as Comparative Examples having a diameter of 30 mm and a thickness of 10 mm and no silicon carbide coating, were oxidized at a temperature of 1,400° C. for 100 hours to measure a weight gain by oxidation, from which a weight gain by oxidation per unit area was calculated. The obtained results are shown in Table 1.
Further, samples were also prepared wherein the curved surface of each of the silicon nitride sintered bodies (Nos. 1-10) having a diameter of 35 mm and a thickness of 8 mm was covered with a silicon carbide coating having a thickness of 150-300 μm, samples wherein one surface of 6 mm×16 mm of rectangular parallelpiped silicon nitride sintered bodies having a block form of 6 mm×16 mm×10 mm was covered with the silicon carbide coating, and samples of Comparative Examples wherein silicon nitride sintered bodies (Nos. 11, 13, 15, 17 and 19) having the same form as the above block form and no silicon carbide coating. With respect to these samples, the surface covered with the coating was mirror-finished to conduct a wear test at a temperature of 600° C. through a block on ring type machine. In this test, a load was 2 kg, a rotating speed was 1,000 rpm and a test period was 10 hours. From the wear volume of the rectangular parallelpiped samples was calculated a specific wear rate. The obtained results are shown in Table 1.
TABLE 1
__________________________________________________________________________
Thermal
expansion
coeffi- Weight
Specific
Composi-
Surface
ceint of Crystal-
gain by
wear
tion of
to be
sintered
CVD process
Temper-
line oxidation
rate
No. additive
treated
body (/°C.)
raw gas
ature
type (mg/cm.sup.2)
(mm.sup.2 /N)
__________________________________________________________________________
Invention 1
MgO worked
4.0 × 10.sup.-6
SiCl.sub.4, C.sub.3 H.sub.8
1,350
β
0.6 3 × 10.sup.-9
2 " sintered
" " 1,350
β
0.7 5 × 10.sup.-9
3 MgO, Y.sub.2 O.sub.3
worked
3.9 × 10.sup.-6
Si(CH.sub.3).sub.4
1,400
α,β
0.5 2 × 10.sup.-9
4 " sintered
" " 1,400
α,β
0.6 2 × 10.sup.-9
5 Y.sub.2 O.sub.3
worked
4.1 × 10.sup.-6
SiCl.sub.4, C.sub.3 H.sub.8
1,400
β
0.6 3 × 10.sup.-9
6 " sintered
" " 1,400
β
0.4 6 × 10.sup.-10
7 MgO, Al.sub.2 O.sub.3
worked
4.3 × 10.sup.-6
SiCl.sub.2, (CH.sub.3).sub.2
1,350
α,β
0.4 5 × 10.sup.-10
8 " sintered
" " 1,350
α,β
0.5 8 × 10.sup.-10
9 Al.sub.2 O.sub.3, Y.sub.2 O.sub.3
worked
3.7 × 10.sup.-6
SiCl.sub.4, C.sub.3 H.sub.8
1,400
β
1.2 7 × 10-9
10 " sintered
" " 1,400
β
1.4 6 × 10.sup.-9
Comparative
Example 11
MgO worked
4.0 × 10.sup.-6 >5 4 × 10.sup.-7
12 " sintered
" >5 "
13 MgO, Y.sub.2 O.sub.3
worked
3.9 × 10.sup.-6 >5 9 × 10.sup.-8
14 " sintered
" 2.3 "
15 Y.sub.2 O.sub.3
worked
4.1 × 10.sup.-6 4.2 6 × 10.sup.-8
16 " sintered
" >5 "
17 MgO, Al.sub.2 O.sub.3
worked
4.3 × 10.sup.-6 >5 3 × 10.sup.-7
18 " sintered
" >5 "
19 Al.sub.2 O.sub.3, Y.sub.2 O.sub.3
worked
3.7 × 10.sup.-6 >5 8 × 10.sup.-8
20 " sintered
" >5 "
__________________________________________________________________________
As seen from the results of Table 1, the silicon nitride sintered bodies covered with the silicon carbide coating by CVD process according to the invention exhibit excellent oxidation resistance and wear resistance as compared with the silicon nitride sintered bodies having no coating.
Carbon was applied to a surface of a silicon nitride sintered body having a composition and a thermal expansion coefficient as shown in the following Table 2 and then reacted with molten Si at a temperature as shown in Table 2 to form a coating of β-type crystalline silicon carbide on the surface of the sintered body, which was polished to obtain a silicon nitride sintered body covered with a coating of silicon carbide (Nos. 21-23) according to the invention. These silicon nitride sintered bodies were subjected to the oxidation test and the wear test in the same manner as in Example 1, together with Comparative Examples of silicon nitride sintered bodies having no coating of silicon carbide (Nos. 24-26). The measured results of weight gain by oxidation and specific wear rate are shown in Table 2.
TABLE 2
__________________________________________________________________________
Thermal
expansion
Reaction
Weight
Specific
Composi-
Surface
coefficient
Temper-
grain by
wear
tion of
to be
of sintered
ature
oxidation
rate
No. additive
treated
body (/°C.)
(°C.)
(mg/cm.sup.2)
(mm.sup.2 /N)
__________________________________________________________________________
Invention 21
MgO worked
4.0 × 10.sup.-6
1,600
0.9 8 × 10.sup.-7
22 MgO, Y.sub.2 O.sub.3
sintered
3.9 × 10.sup.-6
1,650
0.8 9 × 10.sup.-8
23 Al.sub.2 O.sub.3, Y.sub.2 O.sub.3
worked
3.7 × 10.sup.-6
1,700
1.3 5 × 10.sup.-7
Comparative
Example 24
MgO worked
4.0 × 10.sup.-6
>5 4 × 10.sup.-7
25 MgO,Y.sub.2 O.sub.3
sintered
3.9 × 10.sup.-6
>5 9 × 10.sup.-8
26 Al.sub.2 O.sub.3, Y.sub.2 O.sub.3
worked
3.7 × 10.sup.-6
>5 8 × 10.sup.-8
__________________________________________________________________________
As apparent from the results of Table 2, the silicon nitride sintered bodies covered with the silicon carbide coating according to the invention, which were prepared by the surface reaction process, have considerably improved oxidation resistance as compared with the silicon nitride sintered bodies having no silicon carbide coating, but the improvement of wear resistance is not observed.
Carbon was applied to a surface of a silicon nitride sintered body having a composition and a thermal expansion coefficient as shown in the following Table 3 and then reacted with the silicon nitride sintered body at a temperature as shown in Table 3 to obtain a silicon nitride sintered body having a coating of β-type crystalline silicon carbide (Nos. 27-29). These sintered bodies were subjected to the oxidation test and the wear test in the same manner as in Example 1, together with silicon nitride sintered bodies having no coating of silicon carbide (Nos. 30-32) as Comparative Examples. The measured results of weight gain by oxidation and specific wear rate are shown in Table 3.
TABLE 3
__________________________________________________________________________
Thermal-
expansion
Reaction
Weight
Specific
Composi-
Surface
coefficient
Temper-
grain by
wear
tion of
to be
of sintered
ature
oxidation
rate
No. additive
treated
body (/°C.)
(°C.)
(mg/cm.sup.2)
(mm.sup.2 /N)
__________________________________________________________________________
Invention 27
MgO worked
4.0 × 10.sup.-6
1,750
0.9 7 × 10.sup.-8
28 MgO,Y.sub.2 O.sub.3
sintered
3.9 × 10.sup.-6
1,700
0.9 8 × 10.sup.-8
29 Y.sub.2 O.sub.3
worked
4.1 × 10.sup.-6
1,800
1.1 6 × 10.sup. -8
Comparative
Example 30
MgO worked
4.0 × 10.sup.-6
>5 4 × 10.sup.-7
31 MgO, Y.sub.2 O.sub.3
sintered
3.9 × 10.sup.-6
>5 9 × 10.sup.-8
Example 32
Y.sub.2 O.sub.3
worked
4.1 × 10.sup.-6
2.3 6 × 10.sup.-8
__________________________________________________________________________
As apparent from the results of Table 3, the silicon nitride sintered bodies having the silicon carbide coating according to the invention, which were prepared by the surface reaction process, have a considerably improved oxidation resistance as compared with the silicon nitride sintered bodies having no silicon carbide coating, but the improvement of wear resistance is not observed.
As mentioned above, the silicon nitride sintered body covered with the silicon carbide coating according to the invention possesses not only a high-temperature strength resulting from the silicon nitride sintered body itself but also high oxidation resistance and wear resistance resulting from the silicon carbide, which is applied to high temperature structural members such as engine parts, for example, a gas turbine engine rotor, a turbocharger rotor and the like to thereby improve the oxidation resistance or wear resistance thereof.
Further, according to the invention, the silicon carbide coating is particularly formed on the silicon nitride sintered body by CVD process, whereby the oxidation resistance and the wear resistance can simultaneously be improved.
Claims (17)
1. A ceramic article comprising:
a silicon nitride sintered body; and
a silicon carbide coating on a surface of said silicon nitride sintered body;
wherein the thermal expansion coefficient of said silicon nitride sintered body is greater than 3.7×1031 6 /° C.
2. The ceramic article of claim 1, wherein said silicon nitride sintered body has a crystalline intergranular phase.
3. The ceramic article of claim 2, wherein said crystalline intergranular phase consists essentially of at least one phase selected from the group of phases consisting of forsterite (2MgO·SiO2), enstatite (MgO·SiO2), yttrium silicate (Y2 Si2 O7), yttrium-silicon-oxygen nitrogen (Y--Si--O--N) or a solid solution thereof.
4. The ceramic article of claim 1, wherein said silicon carbide coating has a thickness in the range of 10-300 microns.
5. The ceramic article of claim 1, wherein said silicon carbide coating consists of α-type silicon carbide.
6. The ceramic article of claim 1, wherein said silicon carbide coating consists of β-type silicon carbide.
7. The ceramic article of claim 1, wherein said silicon carbide coating was applied on said surface by a chemical vapor deposition process.
8. The ceramic article of claim 1, wherein said ceramic article has a weight gain by oxidation in the range of 0.4-1.4 mg/cm2.
9. The ceramic article of claim 1, wherein said ceramic article has a specific wear rate in the range of 5×10-10 -8×10-7 mm2 /N.
10. A ceramic article comprising:
a silicon nitride sintered body having a crystalline intergranular phase consisting essentially of at least one phase selected from the group of phases consisting of forsterite (2MgO·SiO2), enstatite (MgO·SiO2), yttrium silicate (Y2 Si2 O7), yttrium-silicon-oxygen-nitrogen (Y--Si--O--N) or a solid solution thereof; and
a silicon carbide coating on a surface of said silicon nitride sintered body;
wherein the thermal expansion coefficient of said silicon nitride sintered body is greater than 3.7×10-6 /° C.
11. The ceramic article of claim 10, wherein said silicon carbide coating has a thickness in the range of 10-300 microns.
12. The ceramic article of claim 10, wherein said silicon carbide coating consists of α-type silicon carbide.
13. The ceramic article of claim 10, wherein said silicon carbide coating consists of β-type silicon carbide.
14. The ceramic article of claim 10, wherein said silicon carbide coating is applied on said surface by a chemical vapor deposition process.
15. The ceramic article of claim 10, wherein said ceramic article has a weight gain by oxidation in the range of 0.4-1.4 mg/cm2.
16. The ceramic article of claim 10, wherein said ceramic article has a specific wear rate in the range of 5×10-10 -8×10-7 mm2 /N.
17. A ceramic article comprising:
a silicon nitride sintered body having a crystalline intergranular phase consisting essentially of at least one phase selected from the group of phases consisting of forsterite (2MgO·SiO2), enstatite (MgO·SiO2), yttrium silicate (Y2 Si2 O7), yttrium-silicon-oxygen-nitrogen (Y--Si--O--N) or a solid solution thereof; and
a silicon carbide coating on a surface of said silicon nitride sintered body, said coating having a thickness in the range of 10-300 microns;
wherein the thermal expansion coefficient of said silicon nitride sintered body is greater than 3.7×10-6 /° C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61-33716 | 1986-02-20 | ||
| JP61033716A JPS62197370A (en) | 1986-02-20 | 1986-02-20 | Silicon nitride sintered body |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US4843040A true US4843040A (en) | 1989-06-27 |
Family
ID=12394127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US07/012,159 Expired - Lifetime US4843040A (en) | 1986-02-20 | 1987-02-09 | Silicon nitride sintered bodies |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4843040A (en) |
| EP (1) | EP0239226B1 (en) |
| JP (1) | JPS62197370A (en) |
| DE (1) | DE3767337D1 (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5064788A (en) * | 1986-09-16 | 1991-11-12 | Lanxide Technology Company, Lp | Production of ceramic and ceramic-metal composite articles with surface coatings |
| US5106687A (en) * | 1989-10-11 | 1992-04-21 | Nippon Pillar Packing Co., Ltd. | Composite material with chemically vapor deposited layer of silicon carbide formed thereon |
| US5139871A (en) * | 1988-01-13 | 1992-08-18 | The United States Of America As Represented By The Secretary Of The Navy | Thermochemically treated oligomeric and/or polymeric derived silicon carbide fibers |
| DE4141366A1 (en) * | 1991-12-14 | 1993-06-17 | Mathias Dr Herrmann | METHOD FOR THE PRODUCTION OF SILICON NITRIDE INTERBODIES WITH A MODIFIED SURFACE |
| US5229193A (en) * | 1989-11-10 | 1993-07-20 | Shin-Etsu Chemical Co., Ltd. | Silicon carbide member |
| US5300322A (en) * | 1992-03-10 | 1994-04-05 | Martin Marietta Energy Systems, Inc. | Molybdenum enhanced low-temperature deposition of crystalline silicon nitride |
| US5309874A (en) * | 1993-01-08 | 1994-05-10 | Ford Motor Company | Powertrain component with adherent amorphous or nanocrystalline ceramic coating system |
| US5462813A (en) * | 1991-01-31 | 1995-10-31 | Kyocera Corporation | Composite ceramic sintered material |
| US5516595A (en) * | 1986-09-16 | 1996-05-14 | Lanxide Technology Company, Lp | Production of ceramic and ceramic-metal composite articles with surface coatings |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63134585A (en) * | 1986-11-25 | 1988-06-07 | 日本タングステン株式会社 | Sic coated member |
| JP2585584B2 (en) * | 1987-04-10 | 1997-02-26 | 住友電気工業株式会社 | Silicon carbide-coated wear-resistant parts and method for producing the same |
| JPH0776131B2 (en) * | 1987-09-29 | 1995-08-16 | 日本碍子株式会社 | Silicon nitride sintered member |
| DK3253049T3 (en) | 2016-06-03 | 2020-12-21 | Unitron Nv | DIGITAL RADIO FREQUENCY SIGNAL DISTRIBUTION SYSTEM |
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| FR2344512A1 (en) * | 1976-03-20 | 1977-10-14 | Kernforschung Gmbh Ges Fuer | Silicon nitride based material - with a coating of silicon nitride or silicon carbide |
| US4226914A (en) * | 1978-05-19 | 1980-10-07 | Ford Motor Company | Novel spraying composition, method of applying the same and article produced thereby |
| US4288495A (en) * | 1978-05-19 | 1981-09-08 | Ford Motor Company | Article coated with beta silicon carbide and silicon |
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| JPS60224783A (en) * | 1984-04-20 | 1985-11-09 | Shin Etsu Chem Co Ltd | Method for manufacturing silicon carbide coating |
| US4608326A (en) * | 1984-02-13 | 1986-08-26 | Hewlett-Packard Company | Silicon carbide film for X-ray masks and vacuum windows |
| US4634635A (en) * | 1983-09-30 | 1987-01-06 | Kabushiki Kaisha Toshiba | Black ornament |
| US4652276A (en) * | 1986-03-10 | 1987-03-24 | Gte Valeron Corporation | High toughness silicon nitride cutting tools |
| US4699890A (en) * | 1984-09-07 | 1987-10-13 | Ngk Insulators, Ltd. | Silicon nitride sintered body and method of producing the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6045154A (en) * | 1983-08-18 | 1985-03-11 | 大日本印刷株式会社 | Polyester resin composite vessel and manufacture thereof |
-
1986
- 1986-02-20 JP JP61033716A patent/JPS62197370A/en active Granted
-
1987
- 1987-02-09 US US07/012,159 patent/US4843040A/en not_active Expired - Lifetime
- 1987-02-18 EP EP87301371A patent/EP0239226B1/en not_active Expired
- 1987-02-18 DE DE8787301371T patent/DE3767337D1/en not_active Expired - Fee Related
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2344512A1 (en) * | 1976-03-20 | 1977-10-14 | Kernforschung Gmbh Ges Fuer | Silicon nitride based material - with a coating of silicon nitride or silicon carbide |
| US4226914A (en) * | 1978-05-19 | 1980-10-07 | Ford Motor Company | Novel spraying composition, method of applying the same and article produced thereby |
| US4288495A (en) * | 1978-05-19 | 1981-09-08 | Ford Motor Company | Article coated with beta silicon carbide and silicon |
| US4310481A (en) * | 1980-07-23 | 1982-01-12 | Dow Corning Corporation | High yield silicon carbide pre-ceramic polymers |
| US4340636A (en) * | 1980-07-30 | 1982-07-20 | Avco Corporation | Coated stoichiometric silicon carbide |
| US4409003A (en) * | 1982-05-20 | 1983-10-11 | Gte Laboratories Incorporated | Carbonitride coated silicon nitride cutting tools |
| US4515860A (en) * | 1982-09-10 | 1985-05-07 | Dart Industries Inc. | Self protecting carbon bodies and method for making same |
| US4424096A (en) * | 1982-12-23 | 1984-01-03 | Western Electric Co., Inc. | R-F Electrode type workholder and methods of supporting workpieces during R-F powered reactive treatment |
| US4634635A (en) * | 1983-09-30 | 1987-01-06 | Kabushiki Kaisha Toshiba | Black ornament |
| US4608326A (en) * | 1984-02-13 | 1986-08-26 | Hewlett-Packard Company | Silicon carbide film for X-ray masks and vacuum windows |
| JPS60224783A (en) * | 1984-04-20 | 1985-11-09 | Shin Etsu Chem Co Ltd | Method for manufacturing silicon carbide coating |
| US4699890A (en) * | 1984-09-07 | 1987-10-13 | Ngk Insulators, Ltd. | Silicon nitride sintered body and method of producing the same |
| US4652276A (en) * | 1986-03-10 | 1987-03-24 | Gte Valeron Corporation | High toughness silicon nitride cutting tools |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5064788A (en) * | 1986-09-16 | 1991-11-12 | Lanxide Technology Company, Lp | Production of ceramic and ceramic-metal composite articles with surface coatings |
| US5516595A (en) * | 1986-09-16 | 1996-05-14 | Lanxide Technology Company, Lp | Production of ceramic and ceramic-metal composite articles with surface coatings |
| US5139871A (en) * | 1988-01-13 | 1992-08-18 | The United States Of America As Represented By The Secretary Of The Navy | Thermochemically treated oligomeric and/or polymeric derived silicon carbide fibers |
| US5106687A (en) * | 1989-10-11 | 1992-04-21 | Nippon Pillar Packing Co., Ltd. | Composite material with chemically vapor deposited layer of silicon carbide formed thereon |
| US5229193A (en) * | 1989-11-10 | 1993-07-20 | Shin-Etsu Chemical Co., Ltd. | Silicon carbide member |
| US5462813A (en) * | 1991-01-31 | 1995-10-31 | Kyocera Corporation | Composite ceramic sintered material |
| US5571611A (en) * | 1991-01-31 | 1996-11-05 | Kyocera Corporation | Composite ceramic sintered material and slider member using the same |
| DE4141366A1 (en) * | 1991-12-14 | 1993-06-17 | Mathias Dr Herrmann | METHOD FOR THE PRODUCTION OF SILICON NITRIDE INTERBODIES WITH A MODIFIED SURFACE |
| US5300322A (en) * | 1992-03-10 | 1994-04-05 | Martin Marietta Energy Systems, Inc. | Molybdenum enhanced low-temperature deposition of crystalline silicon nitride |
| US5309874A (en) * | 1993-01-08 | 1994-05-10 | Ford Motor Company | Powertrain component with adherent amorphous or nanocrystalline ceramic coating system |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3767337D1 (en) | 1991-02-21 |
| EP0239226A3 (en) | 1988-03-23 |
| JPH0459275B2 (en) | 1992-09-21 |
| EP0239226A2 (en) | 1987-09-30 |
| EP0239226B1 (en) | 1991-01-16 |
| JPS62197370A (en) | 1987-09-01 |
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